10.1 General Introduction

This section describes a method of conducting a systematic and comprehensive necropsy.

While it may be ideal to complete a comprehensive necropsy on every animal that dies, this is generally not possible due to time and labour constraints. The following approach is suggested to ensure that sufficient necropsies are done to characterise causes of mortality while minimising the time spent on necropsies.

10.1.1 Number Of Animals To Necropsy:

A decision may be made not to necropsy animals that have died from clearly recognisable conditions such as trauma, accident or smothering.

Where multiple deaths occur from the same disease syndrome and around the same time (within 1-2 days), necropsy of three representative animals will allow characterisation of the syndrome.

If the same disease or syndrome continues to be associated with deaths over subsequent days or later in the voyage, conduct additional confirmatory necropsies at a lower rate (one per 1-2 days) from those animals.

If at any stage there is suspicion of a different disease syndrome, then conduct necropsies of three representative animals i.e. follow the same general protocol.

10.1.2 Comprehensive Vs Partial Necropsy:

This Handbook describes a comprehensive necropsy protocol. The term partial necropsy is used to refer to situations where some of the procedures described in the comprehensive protocol are performed but not all.

It is expected that most necropsies performed during export voyages will be partial necropsies.

It is strongly recommended that every necropsy should include as standard, all activities up to and including the initial dissection and display of the body cavities. Then any decision about which of the additional procedures (as outlined in the fourth and final stage of the necropsy: Detailed examination and sampling) will depend on possible differential diagnoses or suspected causes of death. This approach ensures that the necropsy will allow assessment of the tissues involved in the most common and important causes of mortality (lungs, abdominal organs and limbs).

Additional procedures or activities may be performed in the necropsy depending on the history, signs and suspected cause of death.

10.1.3 Collection Of Samples At Necropsy

Samples may or may not be collected at necropsy. A gross necropsy without collecting any samples may allow identification of any pathology that is present and even a generic cause of death, but may not allow determination of the precise cause of death or the infectious agents involved.

A range of biological samples may be collected at necropsy including swabs, blood, urine, and excised sections of various organs or tissues. Recommendations concerning samples are based on the assumption that it is possible to collect, package and send samples to a pathology laboratory. For necropsies that are performed on farm or in assembly feedlots in Australia, appropriate samples should be collected as suggested in this Handbook and sent to a laboratory.

On board export ships, it will be necessary to store samples for up to several weeks before they can be unloaded. This will require planning and permission from the exporter and the Captain to store samples on board. If samples are to be brought back into Australia this will require importation authorisation from the Department of Agriculture and Water Resources (DAWR). Samples managed in this way are likely to be limited to formalin fixed tissues and swabs in viral transport media.

There may also be pathology laboratories operating in destination countries that can receive samples collected during the voyage or after unloading at destination. Discussions should be held with veterinary pathologists in the destination country to determine what services may be available.